The present invention relates generally to communication networks and, more particularly, to monitoring communication networks.
The providers and maintainers of data network services need to be able to collect detailed statistics about the performance of the network. These statistics are used to detect and debug performance problems, provide performance information to customers, help trace network intrusions, determine network policy, and so on. A number of network tools have been developed to perform this task. For example, one approach is to use a “packet sniffer” program such as “tcpdump” that extracts packets from the network, formats them, and passes them to a user-level program for analysis. While this approach is very flexible, it is also very slow-requiring extensive processing for each packet and numerous costly memory transfers. Moreover, moderately priced hardware, such as off-the-shelf personal computer hardware, cannot keep pace with the needs of high-speed networks, for example such as the emerging Gigabit Ethernet standard.
Another approach is to load a special-purpose program into the network interface card (NIC) of a network monitoring device. Processing such as filtering, transformation and aggregation (FTA) of network traffic information can be performed inside the NIC. This approach is fast—but inflexible. As typically implemented in the prior art, the programs are hard-wired to perform specific types of processing and are difficult to change. Network operators typically require a very long lead time as well as interaction with the NIC manufacturer in order to change the program to perform a new type of network analysis.